Unit not attacking?

In a TD that I am making I am trying to make one tower only attack bosses effectively. It can attack when I set it on the defult attack settings. I checked the bosses type of unit. It also has a ability that attacks only bosses.

I have been thinking of a replacement system where it is only active on those levels but, I am not good with varibles.

Sorry if this goes in to a trigger based topic.

Instead of goin throught he triggering hassle etc.

Why not just make ur bosses "Hero" type units and set your targetting fields for towers and abilities to Hero only.

does that solve your problem or am I missing something?

I did try that but, the tower won't attack. Maybe the ability is in the way. It is web but, it only works on heros and I have a similar web on a different tower.

Trigger it.

Get the tower's attack, and if it's a non-hero target, make a unit group of heroes in range and order it.